MEDICAL LABORATORY TECHNICIAN – MLT ASCP-MLT Exam Questions

1. The red portion of the NFPA diamond represents fire hazards.

The fire classification system for NFPA is as follows:

0 - Will not burn

1 - Must be preheated for ignition; flashpoint above 200°F (93°C)

2 - Must be moderately heated for ignition, flashpoint above 100°F (38°C)

3 - Ignition may occur under most ambient conditions, flashpoint below 100°F (38°C)

4 - Extremely flammable and will readily disperse through air under standard conditions, flashpoint below 73°F (23°C)

A laboratory labels its secondary containers of hazardous chemicals using a color-coded system, with a different color representing each different type of hazard. The coding system follows the color-coding used by the National Fire Protection Agency's "fire diamond." What hazard would be represented by the red section on the hazard label?

2. Acute hemolytic transfusion reactions are most commonly due to ABO-incompatible blood being transfused to a recipient with naturally occurring ABO alloantibodies (anti-A, anti-B, anti A,B).

Acute intravascular hemolysis as the result of a blood transfusion is most often associated with which of the following causes?

3. Porphobilinogen

4. Hybridization is a technique used to determine presence of target DNA or RNA by adding a synthetic strand that binds by complementary base pairing to the target.

Microbiology

In molecular diagnostic testing, hybridization employs complementary base pair binding of a synthetic strand to DNA or RNA.

5. Caffeine benzoate solution is used to split the unconjugated bilirubin protein complex releasing the bilirubin so that it can react with diazotised sulphanilic acid. The tartrate buffer creates an alkaline solution and converts the red acid bilirubin to a green coloured compound which can be measured spectrophotometrically.

Which substance is used in the Jendrassik-Grof method to accelerate the reaction of unconjugated bilirubin with the diazo reagent?

6. Incompatiblity involving the ABO blood group system can cause the most severe type of transfusion reaction.

The cause of the most severe life-threatening hemolytic transfusion reactions is:

7. The recommended disinfectant for blood and body fluid contamination is:

8. The image shown in this question is depicting a rosette formation. Here the red blood cells are surrounding and adhering to the outside of the white blood cell.





What is the best description of the phenomenon seen in this illustration?

9. A laboratory scientist is working the night shift at a local hospital when the power goes out.

What is the course of action to continue to provide laboratory results?

10. High triglycerides may be caused by disorders such as type 2 diabetes, hypothyroidism, Cushing's sydnrome, liver disease, uremia, dysglobulinemia, nephrotic syndrome, and alcoholism can cause hypertriglyceridemia.

A 46-year old known alcoholic with liver damage is brought in the ER unconscious. One would expect his lipid values to be affected in what way?

11. Anything that can cause significant turbidity in a blood sample, such as high leukocyte count or lipemia can potentially interfere with the accuracy of a spectrophotometric hemoglobin assay.

Hematology

Which of the following may interfere with the accurate measurement of hemoglobin?

12. Which of the following tests detect LTBI:

13. Hemolytic anemia, myelodysplasia, and liver disease may each fit this peripheral blood picture. Each of these conditions can display peripheral blood macrocytosis. It is easy to observe the overall larger size of the red blood cells in this image compared to the normal lymphocyte also present.

When macrocytes are present, they should be examined for their shape (round vs. oval), the hemoglobin content (central pallor), and whether or not there are any inclusions present in the cell.

Iron deficiency would not be the correct answer in this case, since this condition is associated with microcytosis instead.

The complete blood count was obtained from a patient recently admitted to the emergency room. The red blood cell indices obtained revealed an MCV of 115 femtoliters (fL) (normal range 80 - 90 fL). The patient met the criteria for a peripheral blood smear examination. A representative field is shown on the right.





Which of the following conditions may be indicated by the results seen on this peripheral blood smear?

14. Listeria monocytogenes is the correct answer. The motility agar is showing motility at the top of the tube, but not deeper; typical of this catalase-positive, gram positive bacillus. Streptococcus agalactiae would be catalase negative and a coccus. Erysipelothrix rhusiopathiae would be H2S-positive and catalase negative. Escherichia coli is a gram negative bacillus.





This Gram-positive bacillus grew as a diffusely beta-hemolytic colony from a newborn. It was catalase positive and had tumbling motility on a hanging drop preparation. This is how it appeared on triple sugar iron agar and motility medium.

What is the most likely diagnosis?

15. Fusarium species is the most likely associated with mycotic keratitis.

Trichophyton rubrum is a dermatophyte that commonly causes an itching, scaling skin infection of the feet, known as tinea pedis. Scedosporium apiospermum is commonly associated with sinusitis. Aspergillus niger typically causes otitis externa and can also be associated with sinusitis.

Which of the following species or organisms is the most likely to be the cause of mycotic keratitis (fungal eye infection)?

16. As magnification DECREASES, the opening of the iris diaphragm will...

17. An international, nonprofit organization that establishes standards of best current practice for clinical laboratories is

18. Alpha-fetoprotein is a substance typically used in the triple test during pregnancy and for screening chronic liver disease patients for hepatocellular carcinoma.

Increased concentrations of alpha-fetoprotein (AFP) in adults are MOST characteristically associated with:

19. The production of long, tapered phialides is one of the key identifying features of Trichoderma species. In contrast, Penicillium species, produce phialides with blunt ends.





The phialides of Beauveria species are geniculate, forming a zig-zag pattern.

The arrows in the image on the right point to single, long, tapered phialides that extend laterally from either side of the hyphae. This is an identifying feature of which of the fungi listed below?

20. G6PD deficiency causes an increased suseptibility to the oxidation of hemoglobin, which in turn, causes the precipitation of hemoglobin inside of the red blood cell.

Which one of the following conditions is associated with glucose-6-phosphate dehydrogenase (G6PD) deficiency?

21. White top tubes are used for blood cultures.

Question options:

22. DAT (Direct Antiglobulin Test).

When AHG or Coombs serum is used to demonstrate that red cells are antibody coated in vivo, the procedure is termed:

23. Transport media are required for throat culture swabs but not for rapid strep tests.

24. 0-3.0 mg/L Average risk for CVD

>3.0 mg/L High risk for future CVD

If results are >10.0 mg/L, the patient should be evaluated for an acute inflammatory condition.

Chemistry

A high-sensitivity C-reactive protein (hs-CRP) test result of 5 mg/L (normal = < 1 mg/L) may indicate which of the following?

25. Hemolytic transfusion reactions seldom occur because the incidence of unexpected antibodies in random patients is relatively low, e.g., 3-5% is sometimes cited.

Being transfused with O Rh negative RBC is irrelvant if you have an unexpected antibody like anti-K or anti-c.

Incompatible red cells may "bleed out" but only if bleeding is brisk. Even then, a hemolytic

reaction may occur later once the patient's antibody rebounds and destroys remaining antigen-positive donor red cells.

It's true that some patients have only cold-reactive antibodies that will not react at body temperature. But this does not explain why warm-reactive red cell antibodies cause few reactions

Why do so few patients transfused with un-crossmatched red cells in an emergency experience a hemolytic transfusion reaction? Select the one best reason.

26. The role of the laboratory supervisor or manager is to

27. Ferritin and hemosiderin are considered storage forms of iron.

Which substance(s) is/are considered iron storage compounds?

28. Lower right image

Chains of large, lemon-shaped annelloconidia

29. Which of the following legislation was developed to protect the privacy of all patient information in the health care?

30. What has happened in a titer, if tubes #5-7 show a stronger reaction than tubes #1-4?

31. The results of this PT and aPTT are in normal range. These results can be reported and are not indicative of the need to: order a mixing study or request a redraw.

You have just performed stat PT and aPTT tests on your coagulation instrument.

Your results are as follows:

PT = 12 seconds (normal range 10-13 seconds)

aPTT = 24 seconds (normal range 21-34 seconds)

What would be your next step?

32. Calcium oxalates can be found in normal urine in varying pH levels. Ammonium biurate and triple phosphate can be found in normal alkaline urine. Leucine crystals are always abnormal, and can be found in maple syrup urine disease.

Which one of the following crystals is NOT found in normal urine?

33. Free T4 is affected the least by changes in plasma proteins during pregnancy.

Which of the following thyroid function assays is affected least by pregnancy:

34. Hepatitis B surface antigen, or HBs, is a protein that is present on the surface of the virus. The protein will be present via laboratory testing in the blood with acute and chronic HBV infections

Immunology

What sero-marker is the first marker to become positive in Hepatitis B and is associated with the infective stage?

35. Hb S migrates with D in alkaline and alone in acid electrophoresis.

The gel electrophoresis pattern for hemoglobin S shows which of the following migration patterns?

36. Albumin is a "negative" acute phase protein since it is found in decreased levels during acute phase response. Alpha-1-antitrypsin, fibrinogen, and ceruloplasmin are all "positive" acute phase proteins that are found in increased levels during acute phase response.

Which one of the following usually shows a decrease during an acute phase response?

37. Transmission-based precautions isolation categories include all of the following except:

38. The blood glucose value is critical; negative ketones is consistent with type 2 diabetes. An elderly type 2 diabetic patient is at risk for hyperosmolar non-ketotic coma and osmolality should be measured.

A measurement of urine glucose would not be useful at this point.

A 70-year-old type 2 diabetic patient is comatose and in the emergency department. Stat blood glucose and serum ketones are ordered.

Blood Glucose: 650 mg/dL

Serum Ketones: Negative

What is the best conclusion?

39. On the red cell membrane, there is a bicarbonate / chloride exchanger. This exchanger allows for bicarbonate to leave the red cells while chloride is allowed inside.

In blood, bicarbonate leaves the red blood cell and enters the plasma through an exchange mechanism with:

40. The red blood cell distribution width (RDW) increases as the severity of alpha thalassemia increases because of changing MCV as the bone marrow produces smaller cells. In addition, if Hemoglobin H bodies are present, they result in the formation of schiztocytes (RBC fragments) that can have an effect on the MCV and RDW.

The Red cell Distribution Width (RDW) in alpha thalassemia is

41. Black stopper tubes are used for glucose collections.

Question options:

42. Neutrophils are typically increased in urinary bacterial infections.

What type of white blood cell is seen MOST frequently in urine sediment with infections of the urinary system?

43. The document designed to protect phlebotomists from contacting hepatitis is the:

44. Serum amylase and lipase levels may be slightly elevated in chronic pancreatitis, but not diagnostic enough to predict chronic pancreatitis; wheras high levels are found only during acute pancreatitis episodes. In the later stages of chronic pancreatitis, normal to decreased levels of amylase and lipase are caused by the gradual inability of the pancreas to secrete the enzyme

All of the statements below regarding amylase and lipase in pancreatitis are TRUE EXCEPT:

45. Dce is found in 4% of whites and 44% of blacks.

DCe is found in 42% of whites and 17% of blacks.

DcE is found in 14% of whites and 11% of blacks.

dce is found in 37% of whites and 26% of blacks.

Blood bank

The most common Rh haplotype among whites is:

46. Only non-self antigens can be immunogenic. Self antigens are normally recognized by the immune system as part of the host, so an immune response does not normally occur. Non-self antigens are immunogenic since they have the potential to cause an immune response.

For a substance to be immunogenic it must be:

47. Select area to examine, WBC estimate

48. Microcontainer collection order of draw differs from regular peripheral blood collection order of draw. When performing a capillary draw, the lavender top container is obtained first. This decreases the possibility of clots in the container which would invalidate the results of the complete blood count test.

After the lavender is drawn, other containers with anticoagulants would be collected, and containers without anticoagulants would be collected last.

A phlebotomist must perform a skin puncture to obtain capillary specimens for a complete blood count (CBC), a plasma-based chemistry test, and a serum-based immunology test. The microcollection containers that will be used are lavender top containing EDTA anticoagulant, green top containing heparin anticoagulant, and gold top containing no anticoagulant.

Which microcollection container should be collected first?

49. The clue to the identification of the colony seen in the upper frame is the gram stain in the lower frame, in which are seen short, rounded, gram positive bacilli, many of which possess distinct spores. As the colonies grew aerobically, the presence of spores indicates Bacillus species. The colonies are spreading, smooth, yellow-white and non-hemolytic. The lack of hemolysis and the small size of the bacterial cells suggests a species other than Bacillus cereus, the species causing most human infections. The isolate was identified as Bacillus circulans, which is consistent with the gram stain morphology. Clostridium septicum also produces spores; however, this species is an anaerobe and would grow poorly if at all and not produce spores aerobically. Listeria monocytogenes and Lactobacillus species are gram positive bacilli; however, neither of these produce spores.

The colonies seen in the upper frame, grown after 48 hours incubation aerobically at 35°C,

and the accompanying gram stain in the lower frame are uncommonly associated with human disease, but have been associated with septicemia, bronchopneumonia, osteomyelitis and other infections, particularly in intravenous drug users.

The most likely identification is:

50. The renal threshold is the maximum amount of a substance that the kidney can prevent from entering into the urine.

UA & body fluids

The renal threshold is best described as:

51. A hapten is an incomplete antigen.

All of the following cellular antigens are important to an immunohematologist except:

52. To obtain a serum sample for a stat test on a patient receiving anticoagulant therapy, the recommended tube is:

Question options:

53. Troponin is potentially more specific for myocardial damage than CK-MB and stays elevated longer. It may eventually replace CK-MB as the standard marker of myocardial damage. In addition, troponin T has been known to be elevated in the setting of even mild degrees of renal failure. Troponin and CK-MB both tend to rise approximately 3 hours after a MI (hence why the correct answer is "A", since it is false); however, troponins can stay elevated up to 2 weeks as CK-MB tends to return to baseline around 36 hours.

Chemistry

Which of the following statements is FALSE regarding troponin?

54. In an evacuated tube, blood flow into the tube depends on:

Question options:

55. The structures involved in the production of semen include the prostate, the seminal vesicles, and the bulbourethral gland, along with the testes and epididymis.

Semen is produced as a combination of secretions from the different regions of the male reproductive tract. Each fraction differs in chemical composition and function.

Spermatozoa are produced in the testes. They mature in the epididymis. The testes also produce testosterone and inhibin.

Fluid from the seminal vesicles accounts for approximately 70% of semen volume. The seminal vesicles are the source of fructose in semen. Fructose is used by the spermatozoa as an energy source.

The prostate gland supplies about 20% of the volume of semen. Its fluids include acid phosphatase and proteolytic enzymes that lead to coagulation and subsequent liquefaction of semen. The prostate also contains most of the IgA found in semen.

The bulbourethral gland produces mucoproteins that make up about 5% of the volume of semen.

The pituitary gland is not directly involved in the production of semen; instead hormones are released which stimulate the production of sperm. The urethra is not involved in the production of semen.

Which of the following are directly involved in the production of semen?

56. HbsAg is positive in acute and chronic Hepatitis B infections, since the antigen is found on the actual surface of the virus. HbeAg is present in the blood when the hepatitis B viruses are replicating, indicating an active infection. Anti-Hbc IgM is present due to the immune response to the presence of the hepatitis core antigen and indicates an acute infection. Anti-HBs is generally interpreted as indicating recovery and immunity from hepatitis B virus infection, according to the CDC.

Given the following results, what is the immune status of the patient?

HbsAg: positive

HbeAg: positive

Anti-HBc IgM: positive

Anti-HBs: negative

57. Set of comprehensive safety guidelines designed to protect patients and health care workers

58. The Westgard multi-rule 22S describes the scenario where two consecutive data points fall outside +2SD or -2SD. If this occurs, then the run must be rejected. This situation is most likely caused by a systematic error.

Which of the following describes the Westgard multi-rule 22S?

59. Epidemiology studies only infectious diseases that impact humans

60. The hepatitis B vaccine is a series of immunizations consisting of three injections of the hepatitis B antigen. The antigen causes the recipient of the injection to make antibodies against the antigen, hence why this is an example of active immunity.

Immunology

The hepatitis B virus vaccine was administered to MLS students during Orientation.

Which type of immunity is expected to develop and provide long-term protection?

61. Which of the following organizations now provides the certification exam for laboratory professionals?

62. If your reactions are strong at immediate spin (3+) and then get weaker at AHG (w+), it could mean the presence of a strong cold antibody.

Cold antibodies tend to be IgM and their optimum phase for reactivity is immediate spin. Incubation and washing of the sample may cause the agglutination that occurred at room temperature to break down. This would appear as a weaker reaction at AHG.

If the reaction strengths varied in each panel cell then that could be an indication that there are multiple antibodies present.

Your screen cells are 3+ at immediate spin and weak (W)+ at AHG. Your auto control is negative for both phases. Some of your antibody panel cells are 3+ at immediate spin and negative at AHG.

What should you suspect?

63. The patient's BUN is within normal range (5-20 mg/dL) while the creatinine is about five times the upper normal range (0.6-1.2 mg/dL). Gross elevations in creatinine are almost always accompanied by elevations in BUN when there is kidney impairment. Either the BUN or creatinine value in this case is incorrect. Both tests should be repeated.

A patient's BUN value is 15 mg/dl and his creatinine is 5 mg/dl. If this patient is not undergoing dialysis, what conclusion would you draw from these results?

64. Though it may not be required, TDM should still be used to confirm adequate dosing.

Genotyping does not make TDM redundant.

A PM will metabolize the drug more slowly and therefore will need lower doses. CYP2D6 metabolizes many different drugs; it is not associated with just one class of drugs. Anytime a drug is taken that competes for the same metabolizing enzyme as another drug, there is potential for the concentrations of both drugs to be increased.

A patient has been characterized as a CYP2D6 poor metabolizer (PM) after genotyping.

Which of the following statements is not true?

65. Streptococcus pyogenes is the correct answer. Streptococcus pneumoniae is alpha-hemolytic which demonstrate a green area of partial hemolysis around the colonies. Staphylococcus aureus will produce complete hemolysis but is catalase positive.

Streptococcus agalactiae is beta-hemolytic but only produces a partial clearing of the red blood cells in sheep blood agar.

Complete hemolysis of sheep blood agar as demonstrated by the image below would be seen in which of the following catalase-negative isolates?

66. Which of the following is NOT part of the magnification system of the microscope?

67. Which of the following genotypes cause beta thalassemia minor?

68. Leptin signals the hypothalamus that there are changes in fat stores.

Resistin increases insulin resistance and enhances adhesion molecules present on endothelial cells.

IL-6 responds to tissue injury. IL-6 increases insulin resistance by inhibiting insulin receptor signal transduction in liver cells. It also increases other inflammatory cytokines, interleukin-1 (IL-1) and TNF-a, and stimulates the liver to produce C-reactive protein (CRP).

Adipose tissue and liver cells produce angiotensinogen, a precursor of angiotensin II. Besides increasing blood pressure, angiotensin II may stimulate adipose cell formation and thus increase adipose mass.

Which one of the following adipocyte products is an important messenger in metabolism, signaling the hypothalamus that there are changes in fat stores?

69. A patient with tuberculosis would be placed in:

70. Serum calcitonin is normally produced by the C cells of the thyroid. It functions to reduce serum calcium by inhibiting release of calcium from bone. It is a peptide with a molecular weight of 3400, and has a half life of approximately 12 minutes. It is characteristically elevated in medullary carcinoma of the thyroid. Since medullary carcinoma often occurs as an autosomal disorder, family members of patients with this condition should be screened for serum calcitonin.

Serum calcitonin is typically elevated in which of the following conditions:

71. Provide the equivalent measurement for 1 centimeter.

Question options:

72. Small, dense LDL is most likely to interact with arterial walls, leading to deposition of cholesterol, and initiating or worsening atherosclerosis. Small, dense LDL is associated with more than a three-fold increase in the risk of coronary heart disease.

Large, buoyant LDL is less atherogenic than small, dense LDL.

The LDL phenotype A is normal. It is the so called 'B' pattern that is associated with increased risk.

Which of the following is most likely to interact with arterial walls, leading to deposition of cholesterol, and initiating or worsening atherosclerosis?

73. Each of the drugs/drug classes listed above have been known to cause drug-induced hemolytic anemia, although cephalosporins are the MOST COMMON cause. Cephalosporins can cause drug-induced hemolytic anemia when a patient produces antibodies to the particular cephalosporin drug in the presence of red blood cells. The drugs can alter the membrane appearance of the red blood cells, causing the body to mistake them as foreign. Complement becomes activated due to these antibodies; red cells are then destroyed causing hemolytic anemia. Dark urine, caused by intravascular hemolysis, is one of the most common symptoms associated with this condition.

Which one of the following drugs/drug classes is the MOST COMMON cause of drug-induced hemolytic anemia?

74. Gram-positive bacteria retain the primary crystal violet stain that is applied in the Gram stain because of the cross-linking of the thick peptidoglycan layer in their cell walls. Their cell walls contain less lipids than that of a gram-negative bacteria, and this reduces the permeability of their cell wall to the organic solvents that are used as a decolorizer. When the counterstain is added, it may enter the gram-positive cell, but does not change the color

of the cells.

A thick peptidoglycan is MOST often associated with which of the following types of bacteria?

75. What is the first thing a phlebotomist should do in the event of an accidental needle stick?

76. Bacitracin susceptibility is a presumptive test for the identification of Lancefield group A Streptococcus.

Which of the following is a presumptive test for the identification of Lancefield group A Streptococcus:

77. The laboratory uses flammable chemicals for processing and staining patient specimens.

One type of chemical used is ethanol.

What is the proper way to store this chemical in the laboratory?

78. Know what you are handling - read label carefully.

What is the first thing you do before you handle or open a chemical:

79. Class C fires involve:

Question options:

80. In which of the following laboratory situations is a verbal report permissible?

81. Neutrophils reside in the peripheral circulation for only 7-8 hours ( approx. 7.5 hours) before entering the tissues and body cavities. This process is called diapedesis.

Hematology

How long are healthy neutrophils expected to reside in the peripheral blood of an adult?

82. What is the best description of the purpose of the Commission on Office Laboratory Accreditation (COLA) pertaining to the clinical laboratory?

83. There are many causes of CSF lymphocytosis. Lymphocytosis is seen in viral, fungal, and

tuberculous infections, although a predominance of neutrophils may be present in the early stages of these infections. Lumbar puncture to obtain CSF samples is often contraindicated in those with a suspected brain abscess.

CSF lymphocytosis is associated with all of the following except:

84. The intended response is Vitamin B12 and folate deficiencies. Each of these conditions lead to a megaloblastic production of the red blood cells in the bone marrow. Since vitamin B12 and folate are needed in order to produce a synchronous development of the nucleus with the cytoplasm in hematologic cells, oval-macrocytosis often occurs if these nutrients are not in adequate supply within the body. This can also affect neutrophils, allowing for the characteristic hypersegmented nucleus.

The photographic field contains several oval-macrocytes and a hypersegmented neutrophil with greater than 5 nuclear segments. Oval macrocytes are most commonly associated with pernicious anemia and malabsorption syndromes leading to vitamin B12 and folic acid deficiencies.

Clinical information relating to chronic infection, aplastic anemia, and other hematologic maligancies provide the context for the presence of the oval macrocyte.





Macrocytic erythrocytes and hypersegmented neutrophils are not present in thalassemias or in Pelger-Huet anomaly (hyposegmented neutrophils).

Conditions suggested by the macrocytes and the neutrophil in the photograph to the right

include which of the following?

85. Blood plasma will contain coagulation proteins, but not in a clotted tube where serum is present.

Blood serum contains each of the following substances except:

86. The tube to the left is a slant of esculin medium, the tube to the right contains heart infusion broth with 6.5% sodium chloride. The bacterial species characteristically producing the positive reactions seen in each of these tubes is most likely:

87. Gating sets up boundaries around a subset of data points to segregate those events for analysis.

Gating the proper cell population is crucial for flow cytometric analysis. The CD marker information presented on the histogram data is only representative of the cells inside the gate.

When analyzing the raw data of a sample on the flow cytometer, CD marker information on the histograms represents data inside the _____ population.

88. A positive RPR test and a negative FTA-ABS test is most likely the result of:

89. In excess triglycerides, the triglycerides reduce the amount of cholesterol in LDL particles producing small dense LDL molecules. Because of size and density, these molecules more easily enter damaged endothelium and vessel walls and are more easily incorporated as plaque is formed.

Which statement best describes small dense LDL particles that can occur in atherogenic dyslipidemia?

90. Synovial fluid is actually quite viscous and does not have the same consistency as plasma. The reason for its thicker consistency is to provide cushion and reduce friction between the articular cartilage of synovial joints during movement.

Urinalysis & Other Body Fluids

All of the statements below about synovial fluid are true EXCEPT:

91. Cholesterol levels do not fluctuate as triglycerides, fatty acids, lipoproteins, and chylomicrons do after an individual eats a meal. This is the reason that patients are told to fast; the laboratory needs a fasting sample to determine a lipid profile or panel which includes the latter four components.

Which of the following lipid tests is LEAST affected by the fasting status of the patient?

92. Which of the procedures listed below will increase the platelet concentration in the preparation of Platelets?

93. Hives and rash usually indicate an allergic reaction. Hematuria is due to a variety of causes. Fever and chills usually indicate a febrile reaction. Positive DAT due to conditions other than sensitization to red cell alloantigens is not uncommon. Therefore a positive DAT in the posttransfusion specimen with a negative DAT in the pretransfusion specimen is more likely to indicate alloimmunization.

The most definite indication that a patient has been sensitized to a specific red cell antigen is:

94. No HLA matching is performed for corneal tissue transplants as the cornea occupies a privileged site not usually seen by the immune system. This term has been coined "immune privileged".

Corneal tissue may be transplanted successfully from one patient to another because:

95. Antibodies are differentiated based on their heavy chains; different heavy chains create different isotypes. Humans have five different isotypes of immunoglobulins.

Immunology

The part of the molecule responsible for differences among immunoglobulin classes is:

96. hs-CRP is a more sensitive version of the C-reactive protein (CRP) test, a test that has been used for many years to assess inflammation in settings such as lupus, transplantation, infection, etc.

Which of the following cardiovascular risk markers is a more sensitive version of a test that is used to assess inflammation?

97. Provide the equivalent measurement for 1000 milligrams.

Question options:

98. One of the key characteristics to the identification of Nocardia asteroides is its inability to hydrolyze casein, tyrosine or xanthine, as shown in this photograph. Nitrates are reduced to nitrites. Both Nocardia brasiliensis and Actinomadura madurae hydrolyze both casein and tyrosine; Streptomyces griseus hydrolyzes all three of the substrates.

Illustrated in this photograph is an agar quadrant plate containing casein (A), tyrosine (B), nitrate (C) and xanthine (D). None of the substrates have been hydrolyzed and nitrate has been reduced. The most likely identification is:

99. The tube of choice for trace metal analysis is:

100. Bone marrow biopsies are helpful diagnostic tools in:

Evaluation of anemia and thrombocytopenia

Evaluation of cytopenias

Diagnosing leukemias

Can be part of evaluation for FUO

Bone marrow biopsies are NOT used as screens for hematologic issues during routine check-ups.

Hematology

In which of the following situations would a bone marrow aspirate and biopsy possibly be used as an aid for diagnosis? (Select all that apply)

101. The most likely causes of delayed hemolytic reactions are Kidd system antibodies. Both jka and jkb are often responsible for delayed hemolytic transfusion reactions.

Blood Bank

Delayed hemolytic transfusion reactions are usually caused by antibodies directed against what blood group system?

102. One method of calculating a glomerular filtration rate is using creatinine and urine volume to determine creatinine clearance. The equation is as follows:

Creatinine Clearance = (urine creatinine X urine flow rate) / plasma creatinine; where urine flow rate = volume in mL /24 hours x h/60 min)

In this case = creatinine clearance = 124 X (2200/24 x hour/60) / 2 = 94.7 or 95 ml/min

What is the glomerular filtration rate for a patient with a serum creatinine of 2 mg/dL, if the urine creatinine was 124 mg/dL and the urine volume was 2.2 L/24 hrs?

103. Convert the following temperature from Fahrenheit to Celsius

102 degrees F

104. Molarity x Molecular Weight x Volume = Grams

Molecular Weight (aka Formula Weight) =

2(1) + 32 + 4(16) = 98

So, 4 x 98 x 0.2L = 78.4g

What weight of H2SO4 is contained in 200 ml of a 4 molar H2SO4 solution? (Atomic weight: H= 1; S = 32; 0 = 16)

105. The conidia of Exophiala species are produced within phialides that extrude the conidia in tight, ball-like clusters.

The large, drum stick-shaped muriform macroconidia of Alternaria species are arranged in short chains; the small, elliptical conidia of Cladosporium species are arranged in both long and short, branching chains.

Which of the following dematiaceous fungal species produce conidia in clusters?

106. Convert the following temperature from Celsius to Fahrenheit

20 degrees C

Question options:

107. Lipids tend to form a "maltese cross" pattern when viewed in polarized light, which helps to differentiate them from other urine microscopic components.

Substances found in urinary sediment that are more easily distinguished by use of polarized microscope are:

108. Entamoeba gingivalis resembles Entamoeba histolytica both in size and in nuclear characteristics. Entamoeba gingivalis may contain numerous cytoplasmic inclusions such as red blood cells, white blood cells, and bacteria.





I reside in the mouth where I measure approximately 17 micro meters.

109. The beta hemoglobin chain loci are found on which chromosome?

110. "Universal donor", (a misnomer) is usually applied to group O, Rh negative blood. Although it may be necessary to use group O, Rh negative blood in an extreme emergency, it is preferable to use type specific blood for emergencies.

In an extreme emergency, if the ABO and Rh type are unknown which of the following should be given to the patient?

111. Enterobius vermicularis infection occurs through swallowing ova. Pinworm infections including those caused by Enterobius vermicularis, usually occur due to a fecal-oral route of transmission. According to the CDC, "Eggs are deposited on perianal folds. Self-infection occurs by transferring infective eggs to the mouth with hands that have scratched the perianal area. Person-to-person transmission can also occur through handling of contaminated clothes or bed linens. Enterobiasis may also be acquired through surfaces in the environment that are contaminated with pinworm eggs (e.g. , curtains, carpeting). Some small number of eggs may become airborne and inhaled. These would be swallowed and follow the same development as ingested eggs. Following ingestion of infective eggs, the larvae hatch in the small intestine and the adults establish themselves in the colon. The time interval from ingestion of infective eggs to oviposition by the adult females is about one month. The life span of the adults is about two months. Gravid females migrate nocturnally outside the anus and oviposit while crawling on the skin of the perianal area. The larvae contained inside the eggs develop (the eggs become infective) in 4 to 6 hours under optimal conditions . Retroinfection, or the migration of newly hatched larvae from the anal skin back into the rectum, may occur but the frequency with which this happens is unknown."

Enterobius vermicularis infection occurs through:

112. A zone of inhibition is the area around an antibiotic-infused paper disk that does not show any bacterial growth. The antibiotic impregnated on the disk will diffuse into the agar in the area surrounding the disk. If the bacteria are sensitive to the antibiotic, they cannot grow near the disk. The size of the zone is proportional to how sensitive the organism is. If the organism is resistant to the antibiotic, it will grow very closely to the disk.

The size of the zone of suppressed growth on a sensitivity plate using sensitivity disks is referred to as the zone of:

113. Myoglobin rises typically within 2-4 hours after a myocardial infarction and stay elevated for days, with a peak at the 6-9-hour mark post-MI. After myoglobin, troponin is the next fastest to rise afer a mycardial infarction and can rise within 3-4 hours with a peak around 12 hours post-MI. LD (8-12 hours, 24-48 hour peak) and CK (4-6 hours with peak at 24-36 hours) will also rise after MI, but are not as fast to rise as myoglobin and troponin.

Chemistry

A patient is admitted to the hospital with acute chest pain, but which of the following cardiac markers will be elevated FIRST if the patient had an MI?

114. The primary mechanism responsible for glomerular filtration is:

115. Hemoglobin F has a high affinity for oxygen. When Hb F is elevated, cells containing Hb S are more oxygenated and do not sickle as readily as they would if Hb F were not present or present in small quantities.

Which hemoglobin, when elevated, acts as a protection against sickling in patients with HbS?

116. Pink or Red stopper tubes can be used for Blood Bank!

Question options:

117. HCG levels rise rapidly during the first trimester, then the levels start to decline around week 16. The hCG levels slowly decrease and can level off during the remainder of the pregnancy.

The following BEST describes serum hCG levels during pregnancy:

118. Gram positive organisms resist decolorization by ethyl alcohol. The large crystal violet-iodine complex is not able to penetrate the peptidoglycan layer, and is trapped within the cell in gram-positive organisms. Conversely, the outer membrane of gram-negative organisms is degraded and the thinner peptidoglycan layer of gram-negative cells is unable to retain the crystal violet-iodine complex and the color is lost.

What is the purpose of using ethyl alcohol or acetone in the gram stain procedure:

119. This patient is most likely suffering from sickle cell anemia. This cell, which is sickle-shaped, is indicative of the presence of hemoglobin S. Polychromasia is also commonly observed in sickle cell anemia.

After experiencing crippling pain in her chest, Elizabeth's mother rushes her to the Emergency Room. After a complete blood count and differential are ordered, the hematology technologist views many peripheral cells similar in appearance to those found in the image below.

Which condition is most likely present?

120. Rapid vascular constriction, not dilation, immediately occurs when there is vascular injury in order to constrict the amount of blood that escapes the vessels; ultimately preventing massive loss of blood.

Primary hemostatic processes resulting from vascular damage include all of the following

EXCEPT:

121. Antidiuretic hormone, or ADH, has the important role of conserving body water by reducing the loss of water in urine by changing the water permeability of the distal tubule and collecting duct. An increase in ADH causes a concentrated urine since the water is retained and absorbed through the permeable membrane. An decrease in ADH causes the collecting ducts to retain very little water, instead it is excreted as urine.

Chemistry

Which of the following action describes the MAJOR property of antidiuretic hormone?

122. Enterococcus spp. are bile esculin positive and grow in 6.5% NaCl. If they grow on the 6 µg/mL vancomycin screen agar as this isolate does, it is vancomycin resistant. If there is no growth on the 6 µg/mL vancomycin screen agar, the isolate is susceptible to vancomycin. Streptococcus Group D, not Enterococcus will not grow in the 6.5% NaCl and should not be tested for vancomycin resistance. Staphylococcus epidermidis is catalase positive.





The images below represent a gram-positive, catalase-negative, non-motile coccus inoculated to bile esculin agar, 6.5% NaCl broth and to 6 µg/mL of vancomycin in Mueller Hinton agar. It should be reported as:

123. Vitamin K dependent factors are those that require Vitamin K for their synthesis in the liver. Vitamin K is an important factor to gamma-glutamyl carboxylase which adds a carboxyl group to glutamic acid residues on factors II, VII, IX and X, as well as Protein S, Protein C. In adding the gamma-carboxyl group to glutamate residues on the immature clotting factors Vitamin K is itself oxidized. Deficiency of Vitamin K due to malabsorption, liver disease, etc. may contribute to bleeding disorders because clotting factor maturation depends on Vitamin K.

Which of these coagulation factors are referred to as "vitamin-K dependent?"

124. In DIC, or disseminated intravascular coagulation, the prothrombin time is increased due to the consumption of the coagulation factors due to the tiny clots forming throughout the vasculature. This is also the reason that the fibrinogen levels and platelet levels are decreased. Finally FDP, or fibrin degredation products, are increased due to the formation and subsequent dissolving of many tiny clots in the vasculature. The FDPs are the pieces of fibrin that are left after the fibrinolytic processes take place.

Which of the following laboratory results would be seen in a patient with acute Disseminated Intravascular Coagulation (DIC)?

125. Spirochetes such as Borrelia and Treponemes are best visualized using darkfield microscopy. Borrelia, which causes Relapsing fever, can be visualized under darkfield microscopy of wet preps of peripheral blood. Treponema can be visualized by darkfield microscopy of early primary lesions, and aspirates of affected lymph nodes.

Which of the following organisms is best visualized by use of a darkfield microscope:

126. The laboratory employee with an 2-year associate degree who performs clinical testing is the:

127. Which of the following hormones stimulates gluconeogenesis, the formation of glucose from noncarbohydrate sources such as amino acids, glycerol, and fatty acids?

128. Thrombocytes, or platelets, are of course involved with hemostasis, not immunity.

Immunology

Which of the following would not be considered a part of the body's cellular immune system:

129. Identify the following cell types by matching them with their respective image.

130. The difference between glass and plastic red stopper tubes is that the:

Question options:

131. After collection all blood should be stored at 1 - 6oC, unless it is going to be used as a source of platelets.

A refrigerator used to store whole blood must be able to maintain a temperature in the ranges of:

132. Using the formula on the right,





Cells/µL = 370 x 100 / 18 x 0.1

Cells/µL = 37000 / 1.8

Cells/µL = 20556 or 2.06 x 104

A sample of cerebrospinal fluid is diluted 1:100; the standard 9 squares of a hemocytometer are counted on each side for a total of 18 large squares.

Side 1-- 186 nucleated cells counted

Side 2-- 184 nucleated cells counted

total nucleated cells = 370

Using the standard hemocytometer formula shown on the right, what is the nucleated cell count per microliter (µL)?

133. If Kappa or Lambda is predominant and CD5 is co-expressed with CD19 (CD19/CD5 dual positive lymphocyte population), and CD23 is expressed, chronic lymphocytic leukemia is a probable diagnosis. CD19 is normally found on normal B cell populations and CD5 is normally found on mature T cell populations. However, CD5 is present on B cells in B-chronic lymphocytic leukemia or Mantle Cell Lymphoma, both abnormal B cell malignant processes.

CD23 expression is not consistent with Mantel cells as shown on the decision tree on the right.

A monoclonal B-cell population (Kappa or Lambda predominant) with expression of CD19, CD20, CD23, and co-expression of CD5 is consistent with which of the following?

134. The cell shown in this image is a myelocyte. Myelocytes typically have an eccentric nucleus with cytoplasm similar to a mature neutrophils with a slightly bluer tint due to the cell's immaturity.





Myelocytes have both primary and secondary granules present in the cytoplasm. The nucleus is less mature and therefore has a loose chromatin clumping pattern.

Identify the cell in this illustration indicated by the arrow:

135. An automated method for measuring chloride which generates silver ions in the reaction is called:

136. A key laboratory characteristic by which Mycobacterium bovis can be separated from Mycobacterium tuberculosis is:

137. Mrs. Jones, a diabetic, is admitted to the hospital on November 25th. It appears that she has had an AMI but did not feel the severe chest pain because of diabetic neuropathy. She has not felt well since November 20th and her physician believes she possibly had an AMI on November 20th.

Assuming that the infarct was uncomplicated, which of the following cardiac biomarkers would most likely still be elevated and would assist in an AMI diagnosis?

138. The A and B antigens are present on the red cells of an AB patient. H antigen is a precursor to the ABO antigens.

An individual with type AB blood will demonstrate the complete absence of which of the following antigen sites?

139. 21 CFR 606.65 states, "Supplies and reagents shall be used in a manner consistent with instructions provided by the manufacturer."

The correct answer is

A. The reagents must be used according to the manufacturer's instructions for use. If the instructions say one or two drops may be used and the facility procedures also allow one or two drops, then there is no problem with the staff members choosing to use two drops.

While equipment must be calibrated, it does not generally influence the number of drops used.

Staff members often ask co-workers and colleagues from other facilities how to perform tasks, but it is the manufacturer's instructions for the operation of equipment and the use of reagents that must be followed.

A laboratory employee who is performing an internal audit of routine ABO and Rh typing procedures notes that a technologist places two drops of Anti-D in a tube, centrifuges the tube for 20 seconds, and reads the reaction using a magnifying mirror. When questioned about the procedure, the technologist indicates that most staff use two drops of Anti-D reagent because the reactions are stronger with two drops.

In addition to reviewing the facility procedure manual, what should be done to ensure regulatory compliance?

A. Review the anti-D manufacturer's current instructions for use.

B. Check the calibration records for the centrifuge.

C. Call a colleague at another institution to ask what they do.

140. The body compensates for alkalosis or acidosis of the blood PRIMARILY to regain a normal pH, between 7.35 - 7.45.

When the body compensates for a respiratory or metabolic disorder, the MAIN goal is to achieve:

141. Bicarbonate and Chloride form an exchanger to help regulate and buffer the body's pH.

The buffering capacity of blood is maintained by a reversible exchange process between bicarbonate and:

142. What are the certification requirements for clinical laboratory professionals?

143. In radioimmunassay, a fixed concentration of labeled antigen is incubated with a constant amount of antiserum such that the concentration of antigen binding sites on the antibody is limiting. If unlabeled antigen is added to this system, there is competition between labeled antigen and unlabeled antigen for the limited and constant number of binding sites on the antibody, and thus the amount of labeled antigen bound to antibody will decrease as the concentration of unlabeled antigen increases.

Which of the following choices is correct when describing the principles of competitive radioimmunoassay procedures?

144. Malbranchia species share the production of alternate staining arthroconidia as a common feature with the mold form of Coccidioides immitis.

Both Geotrichum species and Trichosporon species produce rectangular-shaped arthroconidia; however, they are regularly rather than alternately staining. Additionally, the arthroconidia of Geotrichum may produce germ tubes from one corner and the arthroconidia of Trichosporon species may produce blastoconidia from adjacent corners, features not shared by either Malbranchia species or Coccidioides immitis.

The hyphae of Microsporum canis, as seen in direct KOH mounts of skin scales, may break

up into arthroconidia; however, they are much narrower in dimension and do not share the alternate staining characteristics.

Microbiology

The hyaline saprobic fungus that has microscopic features similar to the mold form of

Coccidioides immitis is:

145. Rotavirus

146. Platelet neutralization tests are one of the confirmatory tests that can be used to determine if a patient has a circulating lupus antibody, or lupus anticoagulant. The principle in this test involved the use of a freeze-thawed platelet suspension that, when mixed with the patient plasma, will neutralize the anti-phospholipid antibodies (lupus anticoagulant) present and allow for a corrected aPTT result upon re-testing.

A patient has a history of repeated spontaneous abortion. Coagulation studies reveal an elevated APTT, normal PT, normal platelet function, and normal clotting time. Schistocytes were seen on the peripheral blood smear.

Which test should be performed to determine if the patient has lupus anticoagulant?

147. In order to perform a venipuncture on a newly admitted hospital patient, a phlebotomist needs to

148. A test with high specificity accurately detects the absence of disease. The more specific a test is, the fewer false-positive results will occur. A test with high sensitivity accurately identifies the presence of disease. The more sensitive a test, the fewer false-negative results it produces. In the case stated in this question, the immunoassay has high specificity, so it has few false-positives and will accurately detect those individuals who do not have the disease or condition that is being tested for. However, the test has low sensitivity, so it may not identify all individuals who actually have the disease; it may produce many false-negative results.

The accuracy of an immunoassay is its ability to discriminate between results that are true positives and results that are true negatives. Two parameters of test accuracy are specificity and sensitivity.

Which of these statements apply to an immunoassay with high

specificity, but low sensitivity?

149. Rule-out is a process by which antibodies are identified as being unlikely in a given sample because of the absence of an expected antigen-antibody reaction. In other words, the absence of a reaction is noted with a cell that is positive for the corresponding antigen.

Although rule-out procedures may vary somewhat from institution to institution, the following general principles apply:

Non-reactive cells are selected for rule-out. To be classified as non-reactive, a cell must NOT have reacted at any phase of testing in a given panel or screen.

Using the logic that if the rule-out cell is positive for a given antigen, it should have reacted with the corresponding antibody, you can rule-out antibodies that correspond to antigen positive cells.

To increase the probability that rule-out will not mistakenly eliminate a weakly-reacting antibody that exhibits dosage*, use only cells that are homozygous for the corresponding antigen for those systems that generally show dosage. Generally these include: C, c, E, e, Fya, Fyb, Jka, Jkb, M, N, S, and s.

In this case, it is only possible to rule out on screening cell 2 since it demonstrates a negative reaction with the patient serum. Anti-C cannot be ruled out since the C antigen is heterozygous on screening cell 2 with c. Anti-Fya cannot be ruled out since this antigen is not present on screening cell 2. Anti-M and anti-Jka can be ruled out since the antigens are homozyous while demonstrating a negative reaction on screening cell 2.

Rule-out, while very useful, can lead to error. Ruling out an antibody should be combined with other supporting data to increase confidence in the solution; the more data collected, the higher the probability that the final solution is correct.

*Dosage means that there are two "doses" of the same antigen present on the red cells . Antibodies that exhibit dosage react more strongly with homozygous cells (e.g., Jka Jka) than with heterozygous cells (e.g., Jka Jkb) .

Based on the phenotype of the RBC screening cells, and patient results shown on the right, which of the following antibodies CANNOT be ruled out?

150. The red blood cell distribution width (RDW) increases as the severity of alpha thalassemia increases because of changing MCV as the bone marrow produces smaller cells. In addition, if Hemoglobin H bodies are present, they result in the formation of schiztocytes (RBC fragments) that can have an effect on the MCV and RDW.

The Red cell Distribution Width (RDW) in alpha thalassemia is

151. Interferon gamma serves various purposes in immunologic response, including the promotion of natural killer cell activity as well as decreased viral replication by using enzymes to decrease protein replication, both viral or host, inside of the cell.

The lymphokine most important for increased natural killer cell activity and decreased viral replication in cells is:

152. Provide the equivalent measurement for 1 decimeter.

153. Fatty casts contain refractile oval fat bodies or free fat droplets. They are derived from renal tubular cells, and may be seen in nephrotic syndrome.

Identify the urine sediment element:

154. Although any one of the answers might be considered correct, a report of gram-positive cocci in chains provides sufficient information without going beyond what the observation might allow. In off-the record conversation with the physician, a technologist might divulge that the picture is consistent with Streptococcus; however, enterococci may have a similar Gram stain appearance, potentially leading to the wrong choice of empiric antibiotic agents.





The image shows the Gram stain prepared from the positive blood culture.

What is the MOST appropriate report?

155. In this case, the pH may become more alkaline, perhaps above 8.0, if the bacteria in the sample are proliferating during the extended room-temperature wait time.

A urine specimen was collected at 6:00 a.m. and remained at room temperature until it was received in the laboratory at 3:30 p.m.

How may the pH of the specimen be affected by the extended time at room temperature if bacteria are present in the specimen?

156. The correct answer which best fits the characteristics in this question is Mycobacterium tuberculosis.

What is the MOST likely identity of an acid-fast bacilli that showed buff colored, dry, heaped colonies; niacin, nitrate, and urease positive; and took 23 days at 35ºC to grow?

157. Use Perls' Prussian blue stain.

158. India ink can aid in the visualization of the polysacchride capsules of yeast such as Cryptococcus neoformans.

Micro

India Ink is used to:

159. Thyroid-stimulating immunoglobulins, or TSI's, are IgG antibodies that can bind to thyrotropin (TSH) receptors on the thyroid gland. TSIs mimic the action of TSH, causing excess secretion of thyroxine and triiodothyronine. The TSI level is abnormally high in persons with hyperthyroidism due to Graves' disease.

Which of the following is an autoantibody that binds to TSH receptor sites on thyroid cell membranes preventing thyroid-stimulating hormone binding?

160. Blood collected in CPDA-1 may be stored at 1 - 6 oC for up to 35 days.

How long may blood be stored using CPDA-1 preservative prior to transfusion?

161. Delayed hemolytic transfusion reactions (DHTR) usually occur within which time period?

162. Isotonic or normal saline is a 0.85 % solution of sodium chloride in water.

The concentration of sodium chloride in an isotonic solution is:

163. Overcentrifugation may cause either a false negative result (if too much agitation is required for resuspension), or a false positive, (if centrifuged clumps cannot be completely dispersed). High concentration of IgG paraprotein, and failure to adequately wash cells can leave unbound IgG which will neutralize antiglobulin reagent. Delay of addition of antiglobulin reagent may allow previously bound IgG antibody to dissociate from red cells.

Blood bank

Which of the following might cause a false positive indirect antiglobulin test:

164. Which of the following tubes contains an anticoagulant that does not bind calcium?

Question options:

165. Protein in urine can be confirmed using sulfosalicylic acid (SSA) precipitation. The SSA reagent is added to a small volume of urine. Acidification causes precipitation of protein in the sample, which is subjectively graded as trace, 1+, 2+, 3+ or 4+. SSA reaction will detect albumin, globulins, and Bence-Jones proteins.

Which of the following would be the most appropriate method to confirm a positive protein from a urine dipstick?

166. All of the following tubes contain separation gel except:

Question options:

167. Gluconeogenesis is the formation of glucose from noncarbohydrates when carbohydrate intake is absent, a fasting state. The hormone cortisol along with glucagon and epinephrine all stimulate this metabolic pathway. Insulin; however, inhibits this pathway and is therefore the correct answer.

Which of the following hormones inhibits gluconeogenesis, the formation of glucose from noncarbohydrate sources such as amino acids, glycerol, and fatty acids?

168. Hemoglobin electrophoresis uses an electric field to separate hemoglobin molecules based on differences in net electrical charge. The rate of electrophoretic migration is also dependent on the ionic radius of the molecule, the viscosity of the solution through which it is migrating, the electrical field strength, temperature, and the type of supporting medium used.

Electrophoretic separation of hemoglobin fundamentally relies on:

169. Which specimen should be collected last?

Question options:

170. First, determine the number of WBC's from the hemocytometer as follows:

WBC count = (dilution ratio x # of cells counted x 10) / (# mm2 area counted)

Then: WBC count = (20 x 100 x 10) / (8) = 2500 WBC/mm3 (or 2500 WBC/uL or 2.5 x 103 WBC/uL)

Next, to find the WBC count per liter, multiply the WBC count/uL by the number of uL/L (there are 106 uL/L)

So: (2.5 x 103 WBC/uL) x (106 uL/L) = 2.5 x 109 WBC/L

Hematology

A 1:20 dilution is made for a manual WBC count. The four corner squares on both sides of a hemocytometer are counted. A TOTAL of 100 cells are counted in that area.

What is the white blood cell count in terms of a liter (? x 10^9/L)?

171. L/S ratio <2.0 indicates an increased risk of respiratory distress syndrome (RDS) at delivery. L/S ratio <1.5 indicates a very high risk of developing RDS.

Which of the following statements regarding the L/S ratio is TRUE?

The correct answer is highlighted below

A ratio of 2:1 or greater usually indicates adequate pulmonary surfactant to prevent respiratory distress syndrome (RDS)

A ratio of 1.5:1 indicates fetal lung maturity in pregnancies associated with diabetes mellitus.

Sphingomyelin levels increase during the 3rd trimester causing the L/S ratio to fall slightly during the last two weeks of gestation.

A phosphatidylglycerol (PG) spot indicates the presence of meconium in the amniotic fluid

Lecithin is in direct ratio with sphingomyelin

Heparin contamination is characterized by an elevation in the aPTT test and can also cause an increased PT test as well. Reptilase time tests are used to elimate the effects of heparin contamination as the reagents and method are resistant to the effects of antithrombin III, unlike the PT and aPTT tests. Therefore, it would be expected that a patient sample containing pre-analytical heparin contamination will show an increased aPTT (and sometimes PT as well) while showing a normal reptilase time.

A specimen drawn from an indwelling catheter that was contaminated by heparin would be indicated by: